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Never remove user-wired pages from an object when doing

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msync(MS_INVALIDATE).  The vm_fault_copy_entry() requires that object
range which corresponds to the user-wired vm_map_entry, is always
fully populated.

Add OBJPR_NOTWIRED flag for vm_object_page_remove() to request the
preserving behaviour, use it when calling vm_object_page_remove() from
vm_object_sync().

Reported and tested by:	pho
Reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
This commit is contained in:
Konstantin Belousov 2013-07-11 05:47:26 +00:00
parent 3abeb8113d
commit ebf5d94e82
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=253189
2 changed files with 11 additions and 9 deletions
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19
sys/vm/vm_object.c
View File

@ -1054,9 +1054,9 @@ vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size,
*/
flags = OBJPR_NOTMAPPED;
else if (old_msync)
flags = 0;
flags = OBJPR_NOTWIRED;
else
flags = OBJPR_CLEANONLY;
flags = OBJPR_CLEANONLY | OBJPR_NOTWIRED;
vm_object_page_remove(object, OFF_TO_IDX(offset),
OFF_TO_IDX(offset + size + PAGE_MASK), flags);
}
@ -1892,7 +1892,8 @@ vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
vm_page_lock(p);
if ((wirings = p->wire_count) != 0 &&
(wirings = pmap_page_wired_mappings(p)) != p->wire_count) {
if ((options & OBJPR_NOTMAPPED) == 0) {
if ((options & (OBJPR_NOTWIRED | OBJPR_NOTMAPPED)) ==
0) {
pmap_remove_all(p);
/* Account for removal of wired mappings. */
if (wirings != 0)
@ -1902,8 +1903,7 @@ vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
p->valid = 0;
vm_page_undirty(p);
}
vm_page_unlock(p);
continue;
goto next;
}
if (vm_page_sleep_if_busy(p, TRUE, "vmopar"))
goto again;
@ -1912,12 +1912,12 @@ vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
if ((options & OBJPR_CLEANONLY) != 0 && p->valid != 0) {
if ((options & OBJPR_NOTMAPPED) == 0)
pmap_remove_write(p);
if (p->dirty) {
vm_page_unlock(p);
continue;
}
if (p->dirty)
goto next;
}
if ((options & OBJPR_NOTMAPPED) == 0) {
if ((options & OBJPR_NOTWIRED) != 0 && wirings != 0)
goto next;
pmap_remove_all(p);
/* Account for removal of wired mappings. */
if (wirings != 0) {
@ -1929,6 +1929,7 @@ vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
}
}
vm_page_free(p);
next:
vm_page_unlock(p);
}
vm_object_pip_wakeup(object);

1
sys/vm/vm_object.h
View File

@ -205,6 +205,7 @@ struct vm_object {
*/
#define OBJPR_CLEANONLY 0x1 /* Don't remove dirty pages. */
#define OBJPR_NOTMAPPED 0x2 /* Don't unmap pages. */
#define OBJPR_NOTWIRED 0x4 /* Don't remove wired pages. */
TAILQ_HEAD(object_q, vm_object);